As someone who stayed at the Poly (DVC) in January and then RPR- I prefer RPR. Mainly because of the layout- I prefer the tall tower hotel vs a sprawling resort-style hotel such as the Poly. I prefered the Poly room a little more w/ the split bathroom and larger space- although its a toss-up in decoration/style IMO- I liked them both individually for what they were. They are both top notch.
The lobby of the Poly I like better (feels more themed), but nothing at the Poly gets close to beating Tchoup chop.
Did I mention RPR is almost half the price and gets free express passes?
They're both great, but the value is absolutely at RPR.